Biochemistry Paper-1 (Main), 2023 MBBS Batch ABVMU Lucknow

ATAL BIHARI VAJPAYEE MEDICAL UNIVERSITY, LUCKNOW

MBBS DEGREE EXAMINATION - Ist PROFESSIONAL REGULAR EXAM-AUGUST-2024

BIOCHEMISTRY-PAPER-I

SECTION A - Multiple Choice Questions (MCQs)

PAPER CODE: 2411130003

Note: Choose one correct answer in the OMR sheet provided. No overwriting should be done.

(20 x 1 = 20 MARKS) Time: 20 Minutes

• 1. Which lipoprotein is primarily responsible for delivering cholesterol to cells for membrane synthesis and hormone production?

• a) IDL

• b) VLDL

• c) LDL

• d) HDL

• 2. The process of converting acetyl-CoA into malonyl-CoA is called:

• a) Ketogenesis

• b) Lipogenesis

• c) Lipolysis

• d) Beta-oxidation

• 3. All of the following are responsible for cell junction formation except:

• a) Selectins

• b) Integrins

• c) Cadherins

• d) Cathepsins

• 4. Tay-Sachs disease is a disorder of which cell organelle:

• a) Endoplasmic reticulum

• b) Lysosomes

• c) Mitochondria

• d) Peroxisome

• 5. All affect glucose tolerance test except:

• a) Hyperthyroidism

• b) Vitamin B12 deficiency

• c) Acute infections

• d) Liver diseases

• 6. Which complex of the electron transport chain is also part of the citric acid cycle?

• a) Complex IV

• b) Complex III

• c) Complex II

• d) Complex I

• 7. Cytochrome P450 enzymes are most commonly involved in which phase of xenobiotic metabolism?

  a) Phase IV

• b) Phase III

• c) Phase II

• d) Phase I

• 8. Which of the following is a potent inhibitor of Complex I in the electron transport chain?

• a) Dinitrophenol

• b) Oligomycin

• c) Rotenone

• d) Cyanide

• 9. During prolonged fasting, the brain primarily relies on which of the following substrates for energy?

• a) Ketone bodies

• b) Fatty acids

• c) Amino acids

• d) Glucose

• 10. Glucose and fructose are examples of:

• a) Isomers

• b) Inantiomers

• c) Anomers

• d) Epimers

• 11. Which of the following organelles is involved in the detoxification of drugs and poisons in the liver cells?

• a) Golgi apparatus

• b) Rough endoplasmic reticulum

• c) Smooth endoplasmic reticulum

• d) Lysosomes

• 12. Which of the following pairs are enantiomers?

• a) D-Glucose and D-Galactose

• b) D-Glucose and L-Glucose

• c) D-Glucose and D-Mannose

• d) a-D-Glucose and B-D-Glucose

• 13. Elevated levels of which enzyme are most indicative of acute pancreatitis?

• a) Gamma-glutamyl transferase

• b) Lipase

• c) Amylase

• d) Alkaline phosphatase

• 14. In Lineweaver-Burk plots, what do the x-intercept and y-intercept represent, respectively?

• a) -1/Vmax and 1/Km

• b) Vmax and -1/Km

• c) -1/Km and 1/Vmax

• d) 1/Km and 1/Vmax

• 15. Which among the following is most specific test for diagnosing chronic kidney disease?

• a) Urine protein

• b) Creatinine clearance

• c) Blood urea nitrogen (BUN)

• d) Serum creatinine

• 16. Which of the following is recommended as supplement in iron deficiency anaemia?

• a) Vitamin B12

• b) Vitamin C

• c) Vitamin D

• d) Vitamin A

• 17. Which enzyme is responsible for the breakdown of triglycerides in lipoproteins into free fatty acids and glycerol?

• a) Xylase

• b) Phospholipase

• c) Hormone-sensitive lipase

• d) Lipoprotein lipase

• 18. The major route of excretion for many xenobiotics is:

• a) Saliva

• b) Urine

• c) Sweat

• d) Lungs

• 19. Inhibition of which enzyme leads to a build-up of lactate in cells under anaerobic conditions?

• a) Pyruvate dehydrogenase

• b) Phosphofructokinase

• c) Lactate dehydrogenase

• d) Hexokinase

• 20. What is the rate-limiting enzyme in cholesterol synthesis?

• a) Mevalonate kinase

• b) Squalene synthase

• c) HMG-CoA synthase

• d) HMG-CoA reductase

ATAL BIHARI VAJPAYEE MEDICAL UNIVERSITY, LUCKNOW

MBBS DEGREE EXAMINATION - Ist PROFESSIONAL - REGULAR EXAM - AUGUST-2024

BIOCHEMISTRY-PAPER-I

TIME: 3 Hrs

Max. Marks: 100 Marks (80 Theory + 20MCQs)

NOTE:

• Attempt all questions.

• This question paper consists of two sections: Section A- Multiple Choice Questions and Section B- Theory Questions.

• Both the section has different paper code. Write correct paper code on respective sheet.

• Write correct MCQ paper set on OMR sheet and theory questions on the provided answer booklet.

• Answer MCQs on the provided OMR sheet and theory questions on the provided answer booklet.

SECTION B-THEORY QUESTIONS

PAPER CODE: 2411230003

Q.1 Long Answer Questions 15 MARKS

i) Mention the reactions of Glycogenesis and Glycogenolysis in flow diagram. 5 marks

ii) Discuss the hormonal regulation of Glycogen metabolism. 5 marks

iii) Discuss Glycogen storage diseases and their salient features. 5 marks

Q.2 Clinical Case Scenario based Structured Question (15 MARKS)

A 5-year-old boy presents to the OPD with complaint of episodes of muscle weakness, fatigue, and hypoglycemia after prolonged fasting or physical activity. Physical examination reveals hepatomegaly. Lab result show low blood levels of free carnitine, elevated liver enzymes, and low glucose. The diagnosis of primary carnitine deficiency is established on the basis of genetic testing.

i) Discuss beta oxidation of fatty acid containing 16-C and its energetic. 6 marks

ii) Discuss the fate of oxidation of odd chain fatty acids. 2 marks

iii) What is Carnitine? Discuss the role of carnitine in metabolism of fatty acids. 4 marks

iv) What dietary modifications might be recommended for above patient? 3 marks

Q.3 Short Note Question (Approx 500 Words) 5 X 6 = 30 MARKS

i) Discuss various iso-enzymes which are raised in a case of acute myocardial infarction.

ii) Give schematic diagram of shuttle system used for transfer of reducing equivalents from cytosol into mitochondrial matrix.

iii) Discuss Water soluble Vitamins and their deficiency disorders.

iv) Salient features of Cytochrome P-450 and their role in xenobiotic metabolism.

v) Discuss the role of kidneys in acid-base balance

Q.4 Short Answer Questions (Within 100 Words) 5 X 4 = 20 MARKS

i) Significance of HMP shunt pathway

ii) Allosteric regulation of Enzyme activity

iii) Describe ion-gated & voltage-gated ion channels

iv) Reverse cholesterol transport

v) Structure and function of complex V of Electron Transport Chain.

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